I tried with makemkv to back up a bluray 3d. I selected the mvc content and it all went smoothly. But trying to play this back via kodi/xbian on an Optoma projector (my only active 3d display), it doesn't look right. I get the left half of the image in the left eye and the right half of the image in the right eye, so both appear superimposed on top of each other.

I have tried various settings on the projector as well as inverting sync, but no joy.

So can anyone say what the issue might be or if they have done this with success?

Are you sure Kodi is outputting a compatible 3d stream to the beamer ?
Or maybe the source media type not suited ?
Have you tried other 3d content ?
From this VLC wiki, it seems you've got three main ones and they themselves have many sub settings that need to be tweaked:

(12th Apr, 2018 06:47 AM)deHakkelaar Wrote: Are you sure Kodi is outputting a compatible 3d stream to the beamer ?

It would appear so as the image is being synced with the glasses and split between them. This would only happen if a valid 3D signal and sync were being received by the glasses. 3D videos on youtube work and so that is why this is so puzzling. Due to size I can't currently keep the copies, it is more an exercise to see if it can work for the future when I have more storage.

Hmmm, that's weird. But anyway, you get it work and this is the most important thing

I do not have special setup, just having 3D capable TV (no projector), and Kodi is enabling 3D mode automatically only if I set stereo mode in mkv and video is flagged as 3D movie (maybe its needed because of not having 3d in file name)

But seriously, I haven't watched 3D move for a long time, the 3D hype is out for a loooong time

(13th Apr, 2018 12:39 AM)Nachteule Wrote: But seriously, I haven't watched 3D move for a long time, the 3D hype is out for a loooong time

Yes - a pity really. I liked 3D but now that Hollywood and the equipment manufacturers have decided not to continue with it, I shall sadly miss it.
Maybe in the future it will return with holographic home projection system? Mmmmmm........

As for configuration, I have Pi sending video to projector via HDMI and sound goes via I2S to DAC that streams via fibre optic cable to dolby decoder. Then to amp.
I don't know why I need the different settings to you, but the setups are not the same so maybe that is all it is. I do know that not all projectors will play files with 3D 'frame packing', so I am lucky that mine will.